Not accurate enough

PASC says they are not accurate enough to measure the effect of migration on population, particularly in local areas, and they are not detailed enough to measure the social and economic impacts of migration, or the effects of immigration policy.

Current sources of migration statistics were established at a time when levels of migration were much lower than they are today. These sources are not adequate for understanding the scale and complexity of modern migration flows, despite attempts to improve their accuracy and usefulness in recent years.

Net migration

In the year to June 2012, immigration was estimated at 515,000. Around 15% of immigration was by British nationals, around 30% was by nationals of other EU countries, and around 55% was by non-EU nationals. Emigration was estimated at 352,000. Around 44% of emigration was by British nationals, around 24% was by nationals of other EU countries, and around 32% was by non-EU nationals. Net migration, the difference between immigration and emigration, was estimated at 163,000.

Annual estimates of immigration, emigration and net migration are primarily based on a sample of around 5,000 per year migrants identified through the International Passenger Survey, which is a survey of people travelling through UK air and sea ports.

Migration estimates based on the International Passenger Survey subject to a large margin of error and do not provide sufficient detail on the characteristics of people migrating to and from the UK to judge properly the social and economic consequences of migration and the effects of immigration policy. They do not provide accurate estimates of international migration in local areas.

Government target

The Government aims “to reduce net migration from the hundreds of thousands back down to the tens of thousands” by the end of the current Parliament. In the period 2006 to 2010, estimates of net inward migration averaged 209,000 a year.

So while the Government’s target suggests a ten-fold reduction in net inward migration, in practice it only needs to be roughly halved in order for the Government to achieve its aim. The Committee says the migration estimates based on the International Passenger Survey are too uncertain for accurate measurement of progress against the Government’s net migration target.

Room for improvement

Office of National Statistics (ONS) and Home Office data are incompatible in several respects. ONS migration estimates contain no information on the immigration status of migrants. It is not possible to tell how many immigrants identified by the ONS entered the UK in particular visa categories.

Home Office statistics do not indicate the number of visa holders with valid leave to remain in the UK, or the number that overstay their leave to remain.

Some aspects of official migration statistics could be considerably improved if the Home Office and ONS properly recorded and linked the data they already gather. But a full and accurate statistical account of migration to and from the UK also requires the ONS to develop new sources of migration statistics.

Government estimates

Bernard Jenkin MP, Chair of PASC, said:

“Most people would be utterly astonished to learn that there is no attempt to count people as they enter or leave the UK. They are amazed when they are told that government merely estimates that there are 1/2 million immigrants coming into the UK each year.

This is based on random interviews of around 800,000 people stopped and interviewed at ports and airports each year. Only around 5,000 of those are actual migrants, many of whom may be reticent to give full and frank answers, to say the least.

Some experts will say that this report is understated. As an island nation, with professional statisticians and effective border controls, we could gain decent estimates of who exactly is coming into this country, where they come from, and why they are coming here. As it is, the top line numbers for the Government’s 100,000 'net migration' target are little better than a best guess - and could be out by tens of thousands.

Clearly these statistics are not fit for purpose in the longer term. There is also the problem that few people understand what 'net migration' is. It tells you nothing about how the nature of the UK population is changing, because the total immigration figure is partly offset by large numbers of UK nationals leaving.

And if you try to work out, say, how many Egyptians or Syrians came to the UK last year, any numbers are virtually meaningless, because they are based on the tiny number of Syrians or Egyptians who were actually interviewed - assuming they felt able to tell the truth when they answered the questions.

Some would say that successive governments have hardly been trying to fix this - they didn't want people to know the truth. Even now, the really useful information from e-borders data is at least five years off. Given the importance of immigration as a potentially explosive issue, this ought to be given a much higher priority."